The present invention relates generally to seat assemblies having airbags or gas activated cylinders and, more particularly, to seat assemblies having airbags or gas activated cylinders positioned to raise the knees of an occupant upwardly to limit the forward motion of the occupant in the event of rapid deceleration.
In today""s fast paced world of rapid transportation, the forces exerted on the human body during a vehicular crash can result in severe injuries. Of significant concern are head injuries sustained as a result of the rapid deceleration of a vehicle, such as an aircraft, an automobile or the like. When a vehicle rapidly decelerates the occupant is accelerated forward; this may result in the occupant striking his/her head on some object within the vehicle that is positioned in front of the occupant. As a result, safety measures designed to protect a vehicle""s occupants have been the focus of both government regulation and industry research.
Over the years, numerous systems have been developed to limit trauma to the head that may result during a crash or other rapid deceleration. Among these systems are seat belts, airbags, and articulating seats. Seat belts are one of the most common devices used to restrain the occupant""s forward acceleration. The seat belt functions by restraining the forward movement of the occupant, thereby preventing an impact between the occupant""s head and upper torso and objects within the vehicle that are forward of the occupant. In particular, scientific crash tests have conclusively demonstrated the importance of increasing seat belt tension to restrain an occupant""s movement. Airbags, which inflate during a collision, provide a layer of protection between the occupant""s head and upper torso and objects within the vehicle that are forward of the occupant.
Articulating seats use the forward inertia of the seated occupant to rotate the seat forward and upward during rapid deceleration causing some of the forward energy to be redirected to upward and rotational energy. By redirecting the forward acceleration energy, articulating seats reduce the energy that accelerates the occupant forward. For example, U.S. Pat. No. 5,022,077 issued to Beauvais et al. describes an articulating seat that uses the inertial energy of the seat and occupant to rotate the seat upwardly. It discloses several embodiments of articulating seats that use several different forms of brackets that allow the seat to rotate forward and up in response to rapid deceleration of a vehicle. A further example of an articulating seat is described in U.S. Pat. No. 2,789,650 issued to Krous. Krous""s articulating seat uses hydraulic pressure to rotate the seat upwardly. The hydraulic system is initiated automatically upon front impact of the vehicle or through sustained or violent brake application. The current state of the art, including the aforementioned patents, are designed to respond to the rapid deceleration of an automobile and have not been adapted to address the unique conditions of rapid deceleration that may occur within a commercial transport aircraft.
Of significant concern are head injuries sustained during the rapid deceleration of an airplane. To address this concern, the Federal Aviation Administration issued 14 C.F.R. xc2xa7 25.562. Effective Jun. 16, 1988, the regulation requires that all new commercial transport aircraft be equipped with 16 g dynamically qualified seats. FAR 25.652 specifies Head Injury Criteria (HIC) that a passenger may incur under certain rapid deceleration conditions. Specifically, FAR 25.562 requires that during a 16 g rapid deceleration a passenger may not sustain a head injury that exceeds 1000 units, as defined according to a mathematical equation. A problem that arises in instances of rapid deceleration involving commercial transport aircraft is that in the interior configuration of aircraft, passengers are frequently located behind bulkheads such as galleys, lavatories, closets, and the like. These bulkheads are fixed structures and will be unlikely to move, even in the event of rapid deceleration. Seats are often located in such close proximity to a bulkhead that during instances involving rapid deceleration as specified in FAR 25.562 the occupant could be thrown into a bulkhead, and possibly surpass the HIC requirement.
Thus, a need exists to create a system that protects a seated occupant from head trauma that can result from an occupant impacting his/her head on an object within the vehicle that is forward of the occupant upon rapid deceleration. Of particular interest, is the protection of occupants seated behind bulkheads on commercial transport aircraft.
The present invention provides an effective means of protecting a vehicular occupant in the event of rapid deceleration from being thrown forward into an object within the vehicle that is forward of the occupant. Airbag systems designed for use in automobiles require too large a footprint to be feasible in commercial transport aircraft. Seatbelts require the use of a shoulder harness to restrain the forward motion of an occupant""s upper torso and head. Articulating seats that depend upon directional inertia to function may require a certain mass before they will effectively protect an occupant. In particular, inertial driven articulating seats may not function onboard an aircraft if the aircraft is in an abnormal position, such as a side-ways skid, collapse of a landing gear, or similar situations. In contrast, the present invention provides a seat assembly specifically adapted to the unique safety concerns that are present in commercial transport aircraft.
In one embodiment of the invention the seat assembly comprises a seat cushion, a seatback extending upwardly, an air bag, and an actuation mechanism that inflates the air bag in response to a predetermined event. The airbag is located below the seat cushion and towards the front of the seat cushion, so that when the air bag is inflated it lifts the front portion of the seat cushion upwardly. Inflation of the airbag can be initiated by sensors detecting the rapid deceleration of the vehicle.
The seat assembly preferably comprises a seatpan upon which the seat cushion rests. Preferably, the seatpan is connected to the armrest at a hinge point near the rear of the seat cushion. As the airbag is inflated the seat pan is lifted upwardly near its front portion. This action lifts the front portion of the seat cushion thereby raising the occupant""s knees from beneath the legs. The action of raising the occupant""s legs towards his/her upper torso restrains the forward movement of the upper torso, and prevents an impact between the occupant""s head and objects within the vehicle that are forward of the occupant.
In the preferred embodiment of the invention the seatbelt is attached to the rear of the seatpan. Consequently, when the front portion of the seatpan is raised upwardly in response to inflation of the airbag, seatbelt tension is increased. The additional seatbelt tension helps to restrain the forward movement of the occupant""s torso.
The seat frame preferably includes a front lateral tube that supports the seat assembly. The front lateral tube is located beneath the front portion of the seatpan and connects the left side of the seat frame to the right. The front lateral tube can be hollow to allow the placement of the actuation mechanism that inflates the airbag. The limited amount of available space is a special concern in commercial transport aircraft and the placement of the actuation mechanism within the seat frame allows for the more efficient use of this space.
In a second embodiment of the invention the airbag inflates through the surface of the seat cushion by way of a narrow opening formed within the seat cushion. The inflation of the airbag occurs directly beneath the occupant""s legs and results in the legs being raised towards the chest.
In a third embodiment of the invention, the seat assembly includes a gas activated cylinder instead of an airbag. The gas activated cylinder is attached to the underside of the seatpan and may be secured to a rear leg of the seat frame. In response to a rapid deceleration of the vehicle, the gas activated cylinder goes from a nominal or at rest state to an extended state. In the extended state the seatpan and seat cushion are pushed upwardly thereby tightening seat belt tension and raising the occupant""s legs towards the chest.
The prior art of safety restraint does not adequately address the safety concerns in commercial transport aircraft. The present invention is uniquely adapted to reduce the likelihood of contact between an occupant of an airline seat and a bulkhead that is forward of the occupant.